1. Field of the Invention
The present invention relates to an apparatus for the staining of biological slides, and particularly to a slide staining apparatus which may automatically process a plurality of such slides.
2. Description of the Prior Art
In the biological arts, and particularly in the field of medical technology, the investigation of living tissues and fluids for structure and possible pathology has long proceeded with the aid of microscopic investigation. Specifically, samples of tissues and fluids have classically been placed upon small rectangular glass plates, known as slides, which are then placed under a microscope or similar magnifying device where visible structural characteristics may be viewed. In connection with microscopic investigations, the employment of staining compositions developed to aid in the identification process. At the inception, slides were manually treated and stained prior to viewing, however, particularly in the area of medical technology, the great numbers of slides that required staining for viewing in critical disease investigations was inadequate. To this end, those in the art sought to develop methods and associated apparatus of the automatic staining of a plurality of slides.
A machine for the automated multiple staining of slides is presently available which employs a conveyor-type transporting arrangement, whereby the slides are placed on the conveyor and are sequentially indexed past stations for the dispensing of stain composition, buffer, and then rinse solution. This machine is employed in the area of blood sample evaluation, where the parameters of time and volume are most critical. Though it is an improvement over manual staining techniques, the machine suffers from certain defects of operation. Specifically, the slide is locked in position once it is placed on the conveyor and cannot be removed until the entire staining cycle is completed; thus, individual slides could not be removed for special attention. Further, the slides are stained in serial order and, frequently suffer from non-uniform staining due to excess dispensing of the stain composition components at the respective stations. Finally, the mechanism comprising the conveyor frequently causes jamming of slides with resulting delays in slide movement, which itself may contribute to overstaining of a particular sample, and which generally delays the staining process for all slides presently on the machine.
In our parent Application Serial No. 897,884, the disclosure of which is incorporated herein by reference, a biological slide staining apparatus is disclosed that utilizes a slide tray defining a plurality of seats for biological slides to rest upon. The slide tray is inserted into the machine in the horizontal position and may be removed at any time, for example, to retrieve a particular slide. The machine includes a stain dispenser assembly with a plurality of spigots located above the slides when inserted, which are connected to reservoirs for stain, buffer and rinse solutions via one or more fluid pumps. Sequential application of the respective solutions is electronically controlled. A stain removal means comprises fluid drains, a fan and a heater that first removes excess liquid from the sample, and then circulates warm air to fully dry the stained sample. The slide tray comprises an outer frame and inner slide shelf that is adapted to pivot vertically about one end to urge excess fluid to run off.
The closest prior art known to applicants was made of record during the prosecution of Ser. No. 897,884 and is as follows:
U.S. Pat. No. 2,400,315--Paasche; PA0 U.S. Pat. No. 3,053,223--Hensen, et al.
The present invention is directed to certain modifications of applicants' earlier apparatus, that are believed to confer improved speed and efficiency of operation.